How to solve logic grid puzzles

Logic grid puzzles like Einstein’s riddle look daunting, but they are solved with a handful of simple moves repeated in the right order. These are the ones that matter, from first to last.

1. Write down the certain facts first

Clues like “Ada lives in house 2” or “house 1 has the white door” give you a placement straight away. Do these before anything else: every certain fact makes the other clues stronger.

2. Use “one of each” in both directions

Every house has exactly one of each thing, and each thing is in exactly one house. So once Ada is in house 2, nobody else is. And when a house has only one option left in a row, or an option has only one house left, it’s placed. Most puzzles are finished by this move.

3. Squeeze the position clues

• “Directly left of”: the left item can’t be in the last house, and the right item can’t be in the first.
• “Somewhere left of”: same edges, and once you know where one of them can be, it cuts the other’s range.
• “Next door to”: if one is at an end, the other has only one possible house.

4. Carry links across rows

A clue like “the baker drinks tea” ties two rows together. Whatever you learn about the baker’s house is also true for the tea drinker’s, so cross out both together.

5. Look for the house with nowhere else to go

When you feel stuck, go row by row and ask, for each house, “what can still go here?” Combining two or three small eliminations usually leaves one option. That’s the step most people miss.

6. Test a case only as a last resort

Hard puzzles sometimes leave two possibilities. Follow one through: if it breaks a clue, the other is true. Lantern Lane puzzles never require this; there is always a direct step.

See every technique in action in the original Einstein’s riddle walkthrough.